The heat capacity of solid and liquid polystyrene, p‐substituted polystyrenes, and crosslinked polystyrenes

Abstract

Heat capacities were measured for poly(4‐methylstyrene) [300–500K], poly(4‐fluorostyrene) [130–350K], poly(4‐chlorostyrene) [300–550K], poly(4‐bromostyrene) [300–550K], poly(4‐iodostyrene) [300–550K] and poly(styrene‐co‐divinylbenzene) with 1, 2, 4, 8, and 12 wt.% divinylbenzene (technical grade) [300–550K]. Polystyrene and poly(α‐methylstyrene) data were found to match the ATHAS data bank collections. Crosslinking causes no significant change in heat capacity, but substitution does. The heat capacities in the solid state are evaluated using approximate group and skeletal vibration spectra. Glass transitions are discussed, and full thermodynamic functions (Cp, H, S, G) can be calculated for amorphous, crystalline, and deuterated polystyrene as well as poly(α‐methylstyrene). Glassy polystyrene has an entropy of 7.5 J K−1 mol−1 at absolute zero. Changes of the heat capacity at the glass transition are explained and are predicted to go to zero for 50% poly(styrene‐co‐divinylbenzene) at about 550K.

In situ product recovery of n‐butanol using polymeric resins

“…, poly(styrene-co-DVB) (Judovits et al, 1986)) is 3.5-times lower than that of water, significantly less energy is required to heat the resin phase to the temperature required for product separation. Although application of a vacuum was helpful for product collection in our regeneration protocol, flow of an inert carrier gas over heated resins has worked well for others (Nongonierma et al, 2006), and is a more sustainable approach.…”

Photonic Contribution to the Glass Transition of Polymers

“…Q and ∆H are defined in Eq. (6). The value of h x for the iPP sample of T a = 441.5 K was smaller than h u of the sub-crystals (see Table 8).…”

“…5), for iPP with T g = 270 K, h x (= 2h 0 h ) = 12.1 kJ/mol was derived, being much larger than h g ≈ H g a -H g c = 6.2 kJ/mol [34] and h x (= h g + ∆h) = 7.4 kJ/mol, where ∆h = ∆H -Q, ∆H = H m a -H c a (see Eqs. (5) and (6)). The used data are as follows: T c = 403.6 K, T m ∞ = 450 K for α form crystals, ∆H = 4.89 kJ/mol [34], and Q = 3.76 kJ/mol for the sample annealed at 461.0 K for 1 hour [10,35].…”

“…h x could be calculated from Eqs. (5) and (6), but in Fig. 11, using H m a at T m ∞ of the other α or γ form crystals (sub-crystals).…”

Synthesis and characterization of polystyrene carbon nanotube nanocomposite for utilization in the displaced foam dispersion methodology

“…The polystyrene used was originally received in the form of clear plastic pellets. The pellets were purchased from Entec Polymers, Orlando, FL, USA having an approximate 47% crystallinity that was estimated using the method reported elsewhere [33,34].…”